Published online by Cambridge University Press: 06 October 2014
The view that dilatation of scalp arteries is a major source of pain in migraine was examined in a series of clinical and psychophysiological investigations. Examination of patients during unilateral migraine or tension-vascular headache demonstrated evidence of extracranial vasodilatation in only a minority of patients. Studies of psychophysiological reactivity indicated that the amplitude of superficial temporal artery pulsations increased more on the side habitually affected by headache than on the non-symptomatic side after light exercise, and increased more readily in migrainous subjects than in non-headache controls during psychological stress. In patients who had previously shown thermographic signs of an increase in blood flow at the site of headache, scalp arteries dilated readily to mental arithmetic stress and exercise. Although extracranial vasodilatation sometimes contributes to migraine, it does not appear to be the primary source of pain in the majority of patients. Regulation of scalp artery diameter may be most effective in the subgroup of patients whose scalp arteries contribute to pain.